JP2019044119A - Adhesive composition for organic el display device, adhesive layer for organic el display device, polarizing film with adhesive layer for organic el display device, and organic el display device - Google Patents

Abstract

To provide an adhesive layer for an organic EL display device, which can suppress degradation of an organic EL element, has high transparency, low dielectric characteristics and excellent resistance to peeling when subjected to a drop impact.SOLUTION: The adhesive layer for an organic EL display device is formed of an adhesive composition comprising a (meth)acrylic polymer and a UV ray absorbent. The (meth)acrylic polymer comprises an alkyl (meth)acrylate (A) having an alkyl group having 8 carbon atoms or less and an alkyl (meth)acrylate (B) having an alkyl group having 12 to 24 carbon atoms, in which a proportion (a) of the (A) and a proportion (b) of the (B) satisfy an expression (1): 60≤{(a)+(b)} and an expression (2): 1.4≤{(a)/(b)}≤2. The adhesive layer has a Tg of -20 to -5°C, a transmittance of 10% or less at a wavelength of 380 nm, a transmittance of 85% or more at a wavelength of 450 nm, a total ray transmittance of 85% or more, and a haze of 1% or less.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a pressure-sensitive adhesive composition for an organic EL (electroluminescence) display (OLED). The present invention also relates to a pressure-sensitive adhesive layer for an organic EL display device formed from the pressure-sensitive adhesive composition for an organic EL display device, and a polarizing film with a pressure-sensitive adhesive layer having the pressure-sensitive adhesive layer. Furthermore, the present invention relates to an organic EL display device using the pressure-sensitive adhesive layer and / or the polarizing film.

  BACKGROUND In recent years, organic EL display devices having an organic EL panel mounted are widely used in various applications such as mobile phones, car navigation devices, monitors for personal computers, and televisions. In the organic EL display device, a circularly polarizing plate (polarizing plate and polarizing plate) is usually formed on the surface of the organic EL panel to prevent external light from being reflected by the metal electrode (cathode) and viewed like a mirror surface. / 4 wave plate laminate etc.) is arranged. Moreover, a decoration panel etc. may be further laminated | stacked on the circularly-polarizing plate laminated | stacked on the visual recognition side surface of an organic electroluminescent panel. The constituent members of the organic EL display device such as the circularly polarizing plate and the decorative panel are generally laminated via a bonding material such as a pressure-sensitive adhesive layer or an adhesive layer.

  In an image display apparatus such as an organic EL display apparatus, a component or the like in the image display apparatus may be degraded by incident ultraviolet light, and a layer containing an ultraviolet absorber to suppress the deterioration due to the ultraviolet light. It is known to provide. Specifically, for example, it has at least one ultraviolet absorbing layer, the light transmittance at a wavelength of 380 nm is 30% or less, and the visible light transmittance at a longer wavelength side than a wavelength of 430 nm is 80% or more Transparent double-sided pressure-sensitive adhesive sheets for image display devices (see, for example, Patent Document 1) and pressure-sensitive adhesive sheets having a pressure-sensitive adhesive layer containing an acrylic polymer and a triazine-based ultraviolet absorber are known (see, for example, Patent Document 2) .

  Further, in the organic EL display device, a touch panel having a capacitive touch sensor is used in combination. With the spread of capacitive touch sensors, higher performance is required. Therefore, high performance is also required for the pressure-sensitive adhesive layer applied to a capacitive touch sensor. However, due to thinning of the module in the organic EL display device, increasing the screen size, and increasing the definition of the organic EL element, driving noise during display driving of the organic EL panel adversely affects the sensing of the capacitive touch sensor. There is concern that a malfunction may occur. The malfunction due to the driving noise may occur when the dielectric constant of the adhesive layer is high. Therefore, as a pressure-sensitive adhesive for forming a pressure-sensitive adhesive layer having a reduced dielectric constant, for example, a pressure-sensitive adhesive having a (meth) acrylic polymer having an alkyl (meth) acrylate having a long chain alkyl group as a main component is proposed. (E.g., Patent Document 3). According to the pressure-sensitive adhesive layer with a low dielectric constant, the influence of driving noise from the organic EL panel on the capacitive touch sensor can be reduced.

JP, 2012-211305, A JP, 2013-75978, A JP, 2013-082880, A

  Although the adhesive sheet of patent document 1, 2 can control the transmittance | permeability of the light of wavelength 380nm, When the said adhesive sheet is used with an organic electroluminescence display, organic EL element by long-term use However, it was not enough. This is because the pressure-sensitive adhesive sheets described in Patent Documents 1 and 2 can absorb light with a wavelength of 380 nm, but the wavelength range (380 nm) on the shorter wavelength side than the light emitting region (longer wavelength side than 430 nm) of the organic EL element It is considered that the light of ̃430 nm is not sufficiently absorbed, and the transmitted light causes deterioration.

  Therefore, in order to suppress the deterioration of the organic EL element, the transmission of light with a wavelength (380 nm to 430 nm) on the short wavelength side of the light emitting region (longer than 430 nm) of the organic EL element is suppressed. It is necessary to use a layer having high transparency, which can ensure sufficient transmittance of visible light in the light emitting region of the above, for the organic EL display device.

  On the other hand, organic EL display devices are used in various applications. For example, when used in module devices for mobile applications, drop impact resistance is required. Accordingly, the pressure-sensitive adhesive layer used in the organic EL display device is required to have a peeling resistance at the time of a drop impact as a drop impact resistance. In particular, since the pressure-sensitive adhesive layer having a low dielectric constant described in Patent Document 3 has a high glass transition point (Tg), the drop impact resistance (the peel resistance at the time of drop impact) is not sufficient.

  Therefore, the present invention can suppress deterioration of the organic EL element, has high transparency, and further has low dielectric characteristics that can reduce the influence of driving noise of the organic EL panel, In addition, it is an object of the present invention to provide a pressure-sensitive adhesive layer for an organic EL display device which is excellent in peeling resistance at the time of drop impact.

  Further, the present invention provides a polarizing film with a pressure-sensitive adhesive layer having a polarizing film and the pressure-sensitive adhesive layer for the organic EL display device, and further, the present invention provides the pressure-sensitive adhesive layer and / or the polarizing film with the pressure-sensitive adhesive layer. It aims at providing an organic electroluminescence display containing.

  As a result of intensive studies to solve the above problems, the present inventors have found the following pressure-sensitive adhesive layer for an organic EL display device and the like, and have completed the present invention.

That is, the present invention is a pressure-sensitive adhesive layer for an organic EL display device formed from a pressure-sensitive adhesive composition containing a (meth) acrylic polymer and an ultraviolet light absorber,
The (meth) acrylic polymer is an alkyl (meth) acrylate (C) having an alkyl group having 8 or less carbon atoms at the ester end and an alkyl (meth) acrylate (B) having an alkyl group having 12 to 24 carbon atoms at the ester end Obtained by polymerizing a monomer component containing a monofunctional monomer component containing
The ratio (a: wt%) of the alkyl (meth) acrylate (A) and the ratio (b: wt%) of the alkyl (meth) acrylate (B) in 100 wt% of the monofunctional monomer component are represented by the following formulas (1) and the expression (2) are satisfied,
Formula (1): 60 ≦ {(a) + (b)}
Formula (2): 1.4 ≦ {(a) / (b)} ≦ 2
And the pressure-sensitive adhesive layer is
The peak value (Tg) of tan δ when dynamic viscoelasticity is measured at a frequency of 1 Hz is −20 to −5 ° C.
The transmittance at a wavelength of 380 nm is 10% or less, and the transmittance at a wavelength of 450 nm is 85% or more,
The present invention relates to a pressure-sensitive adhesive layer for an organic EL display device having a total light transmittance of 85% or more and a haze of 1% or less.

  In the pressure-sensitive adhesive layer for an organic EL display device, it is preferable that the maximum absorption wavelength of the absorption spectrum of the ultraviolet absorber be in a wavelength range of 300 to 400 nm.

  In the pressure-sensitive adhesive layer for an organic EL display device, the monofunctional monomer component may further include any at least one cohesive monomer selected from a cyclic nitrogen-containing monomer and an alicyclic structure-containing monomer. The proportion of the aggregating monomer in the monofunctional monomer component is preferably 10 to 22% by weight.

  In the pressure-sensitive adhesive layer for the organic EL display device, the monofunctional monomer component may further contain a hydroxyl group-containing monomer. The proportion of the hydroxyl group-containing monomer in the monofunctional monomer component is preferably 1.5 to 10% by weight.

  In the pressure-sensitive adhesive layer for an organic EL display device, the monomer component may further contain a polyfunctional monomer in an amount of 3 parts by weight or less based on 100 parts by weight of the monofunctional monomer component.

  In the pressure-sensitive adhesive layer for an organic EL display device, the pressure-sensitive adhesive composition can further contain a dye compound having a maximum absorption wavelength of an absorption spectrum in a wavelength range of 380 to 430 nm.

  In the pressure-sensitive adhesive layer for an organic EL display device, the pressure-sensitive adhesive composition may further contain a crosslinking agent in an amount of 3 parts by weight or less based on 100 parts by weight of the (meth) acrylic polymer.

  In the pressure-sensitive adhesive layer for an organic EL display device, the pressure-sensitive adhesive composition can further contain a silane coupling agent in an amount of 3 parts by weight or less based on 100 parts by weight of the (meth) acrylic polymer.

  In the pressure-sensitive adhesive layer for the organic EL display device, the pressure-sensitive adhesive composition can further contain a photopolymerization initiator.

  The pressure-sensitive adhesive layer for the organic EL display device preferably has a relative dielectric constant of 3.5 or less at a frequency of 100 kHz.

  The pressure-sensitive adhesive layer for the organic EL display device preferably has a gel fraction of 50 to 95% by weight.

  The pressure-sensitive adhesive layer for an organic EL display device preferably has a 180 degree peel adhesion (peeling speed of 300 mm / min) to non-alkali glass of 7 N / 20 mm or more.

  Preferably, the pressure-sensitive adhesive layer for an organic EL display device has a separator on at least one side.

  The present invention also relates to a polarizing film with a pressure-sensitive adhesive layer for an organic EL display characterized by having a polarizing film and the pressure-sensitive adhesive layer for the organic EL display.

  In the polarizing film with an adhesive layer for an organic EL display device, the polarizing film is provided with a transparent protective film on one side of a polarizer and has a retardation film on the other side, and the organic EL The pressure-sensitive adhesive layer for a display device is preferably provided on the surface of the retardation film opposite to the surface in contact with the polarizer, and / or on the surface of the transparent protective film opposite to the surface in contact with the polarizer.

The polarizing film with a pressure-sensitive adhesive layer for an organic EL display device has a pressure-sensitive adhesive layer having a first pressure-sensitive adhesive layer, a transparent protective film, a polarizer, a second pressure-sensitive adhesive layer, a retardation film, and a third pressure-sensitive adhesive layer in this order. A polarizing film,
It is preferable that at least one pressure-sensitive adhesive layer among the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer, and the third pressure-sensitive adhesive layer is the pressure-sensitive adhesive layer for the organic EL display device.

  In the pressure-sensitive adhesive layer-attached polarizing film for an organic EL display device, it is preferable that the retardation film is a 1⁄4 wavelength plate, and the polarizing film is a circularly polarizing film.

  The present invention also relates to an organic EL display device using at least one of the pressure-sensitive adhesive layer for the organic EL display device or the polarizing film with the pressure-sensitive adhesive layer for the organic EL display device.

The organic EL display device is an organic EL display device with a touch panel including an organic EL panel, a circularly polarizing film provided in order from the viewing side of the organic EL panel, and a touch panel having at least one sensor film,
It is suitable in the aspect by which the pressure-sensitive adhesive layer for an organic EL display device is provided so as to be in contact with at least one sensor film on the viewing side of the circularly polarizing film.

  As described above, the pressure-sensitive adhesive layer for an organic EL display device is suitable as a pressure-sensitive adhesive layer for a touch panel used in contact with at least one sensor film in the organic EL display device with a touch panel.

  The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer for an organic EL display device of the present invention is formed from a pressure-sensitive adhesive composition containing an ultraviolet light absorber in addition to the acrylic polymer which is a base polymer. The ultraviolet absorber can suppress the deterioration due to the ultraviolet light by not transmitting light in the near ultraviolet to ultraviolet regions. Further, the pressure-sensitive adhesive layer for an organic EL display device of the present invention has high transparency, and can suppress deterioration of the organic EL element without interfering with the display performance of the organic EL element. Therefore, the organic EL display device using the pressure-sensitive adhesive layer-attached polarizing film including the pressure-sensitive adhesive layer for the organic EL display device and / or the pressure-sensitive adhesive layer for the organic EL display device of the present invention has excellent weathering deterioration resistance It is possible to extend the life.

  Moreover, in order to lower the dielectric constant, it is considered that the dipole moment of the molecule is decreased and the molar volume is increased according to the Clausius-Mossotti equation. The acrylic polymer according to the present invention has alkyl (meth) acrylate (B) having a long chain alkyl group as a monomer unit, and can lower the dielectric constant of the pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer having a low dielectric constant can reduce the influence of malfunction due to the influence of driving noise from the organic EL panel on the capacitive touch sensor. Therefore, the pressure-sensitive adhesive layer of the present invention can be suitably applied to a touch sensor with high response speed and high sensitivity.

  Further, the acrylic polymer according to the present invention is a polymer in which each monomer unit of two kinds of (meth) acrylates (A) and (B) having different carbon numbers of alkyl groups is contained at a predetermined ratio, The pressure-sensitive adhesive layer of the present invention is controlled to have a glass transition temperature (Tg) of -5 ° C or less, despite having an alkyl (meth) acrylate (B) having a chain alkyl group as a monomer unit . Thus, according to the present invention, a pressure-sensitive adhesive which maintains the adhesive properties as a pressure-sensitive adhesive layer and which has drop impact resistance (peeling resistance at the time of drop impact) while being lowered in dielectric constant as described above A layer is obtained. The pressure-sensitive adhesive layer of the present invention is formed by interlayer filling of a printable glass (cover glass or the like), an optical film, an electrostatic capacitance type touch sensor, and an air layer in the upper portion of the organic EL display in an organic EL display. It is possible to provide a mobile module device excellent in peeling resistance at the time of a drop impact.

(A)-(c) It is sectional drawing which shows typically one Embodiment of the polarizing film with an adhesive layer for organic EL display devices of this invention. It is a sectional view showing typically one embodiment of the organic EL display of the present invention. It is a sectional view showing typically one embodiment of the organic EL display of the present invention. It is a sectional view showing typically one embodiment of the organic EL display of the present invention.

1. Pressure-Sensitive Adhesive Layer for Organic EL Display Device The pressure-sensitive adhesive layer for organic EL display device of the present invention is formed from a pressure-sensitive adhesive composition containing a (meth) acrylic polymer and an ultraviolet light absorber.

(1) Partially Polymerized Monomer Component, and (Meth) Acrylic-Based Polymer The (meth) acrylic-based polymer contained in the pressure-sensitive adhesive composition is an alkyl (meth) acrylate having an alkyl group having 8 or less carbon atoms at the ester end Partially polymerizing a monomer component comprising (A) and a monofunctional monomer component comprising an alkyl (meth) acrylate (B) having an alkyl group having 12 to 24 carbon atoms at the ester end, and / or polymerizing the monomer component Obtained by In addition, "alkyl (meth) acrylate" refers to alkyl acrylate and / or alkyl methacrylate, and (meth) of the present invention has the same meaning.

The alkyl (meth) acrylate (A) and the alkyl (meth) acrylate (B) are the ratio of the alkyl (meth) acrylate (A) in 100% by weight of the monofunctional monomer component in the monomer component a: wt%) and the proportion (b: wt%) of the alkyl (meth) acrylate (B) are used to satisfy the following formulas (1) and (2).
Formula (1): 60 ≦ {(a) + (b)}
Formula (2): 1.4 ≦ {(a) / (b)} ≦ 2
By using the alkyl (meth) acrylate (A) and the alkyl (meth) acrylate (B) in the above range, these monomer units can be introduced into the (meth) acrylic polymer in a balanced manner, and an adhesive The layers can be provided with low dielectric properties and peel resistance on drop impact.

  The sum {(a) + (b)} of the proportion (a) of the alkyl (meth) acrylate (A) and the proportion (b) of the alkyl (meth) acrylate (B) according to the formula (1) is It is 60% by weight or more based on 100% by weight of the monofunctional monomer component in the monomer component. The total amount is preferably 65% by weight or more, and more preferably 70% by weight or more, from the viewpoint of the balance of adhesion characteristics and the drop impact resistance. On the other hand, the total may be 100% by weight, but it is preferably 95% by weight or less from the viewpoint of securing cohesion and crosslinking points, securing of elastic modulus at high temperature, and wettability to adherends. Furthermore, it is preferable that it is 90 weight% or less.

  Further, the ratio (a) of the alkyl (meth) acrylate (A) and the ratio (b) of the alkyl (meth) acrylate (B) according to the formula (2) {(a) / (b)} Is preferably in the range of 1.4 to 2, and more preferably 1.5 to 2, and more preferably 1.6 to 2 from the viewpoint of achieving both reduction in dielectric constant and drop impact resistance.

  The proportion (a) of the alkyl (meth) acrylate (A) is preferably 30 to 60% by weight, and more preferably 30 to 56% by weight. The proportion (b) of the alkyl (meth) acrylate (B) is preferably 20 to 38% by weight, more preferably 22 to 36% by weight.

<Alkyl (meth) acrylate (A)>
As the alkyl group having 8 or less carbon atoms in the alkyl (meth) acrylate (A), either linear or branched can be used, but the addition of tackiness to the pressure-sensitive adhesive layer and resistance to drop impact From the viewpoint, the carbon number of the alkyl group is preferably 2 to 8, and more preferably 4 to 8. Further, the alkyl (meth) acrylate (A) is preferably an alkyl acrylate from the viewpoint of relatively low glass transition point (Tg) and relatively fast radical polymerization reactivity. Further, from the viewpoint of imparting adhesiveness to the pressure-sensitive adhesive layer, the alkyl (meth) acrylate (A) preferably has a homopolymer Tg of −90 to −20 ° C., and more preferably −85 to −30 ° C. And further preferably -80 to -40 ° C. The Tg of the homopolymer is a value measured by differential thermal analysis (TG-DTA) (the same applies to the measurement of the homopolymer Tg).

  Examples of the alkyl (meth) acrylate (A) include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, Isobutyl (meth) acrylate, n-pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, isoamyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (Meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate and the like. These can be used alone or in combination.

<Alkyl (meth) acrylate (B)>
The alkyl group having 12 to 24 carbon atoms in the alkyl (meth) acrylate (B) may be either linear or branched, but branched from the viewpoint of being able to satisfy a low dielectric constant and an appropriate elastic modulus. It is preferably a chain, and more preferably a branched alkyl group having 14 to 22 carbon atoms. Moreover, in the case of a linear alkyl group, it is preferable that the number of carbon atoms is 18 or more from the viewpoint of satisfying a low dielectric constant and an appropriate elastic modulus. The long chain alkyl group of the alkyl (meth) acrylate is considered to increase the molar volume by the branch of the alkyl group and to decrease the dipole moment to obtain a pressure-sensitive adhesive layer having a balance of both. The alkyl (meth) acrylate (B) is preferably an alkyl acrylate from the viewpoint of relatively low glass transition point (Tg) and relatively fast radical polymerization reactivity. The alkyl (meth) acrylate (B) preferably has a homopolymer Tg of −80 to 0 ° C. from the viewpoint of imparting a low dielectric constant and a suitable elastic modulus to the pressure-sensitive adhesive layer, and The temperature is preferably 75 to -5 ° C, more preferably -70 to -10 ° C.

  Examples of the alkyl (meth) acrylate (B) include lauryl (meth) acrylate, isododecyl (meth) acrylate, tridecyl (meth) acrylate, isotridecyl (meth) acrylate, tetradecyl (meth) acrylate, and pentadecyl (meth) acrylate. Isopentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, isohexadecyl (meth) acrylate, isoheptadecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, etc. Be

<Copolymerization monomer>
The monofunctional monomer in the monomer component can contain a copolymerized monomer other than the alkyl (meth) acrylates (A) and (B). The copolymerizable monomer can be used as the remainder of the alkyl (meth) acrylates (A) and (B) in the monofunctional monomer.

  The copolymerization monomer can include, for example, any at least one cohesive monomer selected from a cyclic nitrogen-containing monomer and an alicyclic structure-containing monomer. The cohesive monomer is preferable from the viewpoint that the homopolymer has a high Tg, and the dielectric constant can be lowered, the cohesive force can be ensured, and the elastic modulus at high temperature range (80 ° C.) can be maintained high. The Tg of the homopolymer of the aggregating monomer is preferably 0 to 200 ° C, more preferably 5 to 180 ° C, and still more preferably 10 to 160 ° C.

  As the cyclic nitrogen-containing monomer, those having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a cyclic nitrogen structure can be used without particular limitation. The cyclic nitrogen structure preferably has a nitrogen atom in the cyclic structure. Examples of cyclic nitrogen-containing monomers include lactam vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, methylvinylpyrrolidone and the like; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinyl And vinyl monomers having a nitrogen-containing heterocycle such as imidazole, vinyl oxazole and vinyl morpholine. In addition, (meth) acrylic monomers containing a heterocyclic ring such as morpholine ring, piperidine ring, pyrrolidine ring, piperazine ring and the like can be mentioned. Specifically, N-acryloyl morpholine, N-acryloyl piperidine, N-methacryloyl piperidine, N-acryloyl pyrrolidine etc. are mentioned. Among the cyclic nitrogen-containing monomers, lactam vinyl monomers are preferable.

As said alicyclic structure containing monomer, it has a polymerizable functional group which has unsaturated double bonds, such as a (meth) acryloyl group or a vinyl group, and can use without particular limitation what has an alicyclic structure. . The alicyclic structure is a cyclic hydrocarbon structure and preferably has 5 or more carbon atoms, preferably 6 to 24 carbon atoms, and more preferably 8 to 20 carbon atoms, from the viewpoint of lowering the dielectric constant. More preferably, it is 10-18. Examples of the alicyclic structure-containing monomer include cyclopropyl (meth) acrylate, cyclobutyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, cyclooctyl (meth) acrylate and isobornyl (Meth) acrylic monomers such as (meth) acrylate, dicyclopentanyl (meth) acrylate, HPMPA (chemical formula 1 below), TMA-2 (chemical formula 2 below), HCPA (chemical formula 3 below) . Among these, cyclohexyl (meth) acrylate, HPMPA, TMA-2 and HCPA are preferable, and cyclohexyl (meth) acrylate, HPMPA and TMA-2 are particularly preferable.

  10 to 22 weight% is preferable with respect to the total amount of a monofunctional monomer component, and, as for the ratio of the said cohesive monomer, 12 to 20 weight% is more preferable.

  Moreover, a hydroxyl group containing monomer can be included as a copolymerization monomer in the said monofunctional monomer. As the hydroxyl group-containing monomer, one having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a hydroxyl group can be used without particular limitation. As a hydroxyl group containing monomer, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (4-hydroxybutyl (meth) acrylate Hydroxyalkyl (meth) acrylates such as meta) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxy lauryl (meth) acrylate; And hydroxyalkyl cycloalkane (meth) acrylates such as -hydroxymethylcyclohexyl) methyl (meth) acrylate. In addition, hydroxyethyl (meth) acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether etc. are mentioned. These can be used alone or in combination. Among these, hydroxyalkyl (meth) acrylate is preferred.

  The proportion of the hydroxyl group-containing monomer is preferably in the range of usually 0.1 to 20% by weight from the viewpoint of enhancing adhesion and cohesion with respect to the total amount of monofunctional monomers. In particular, from the viewpoint of controlling the Tg of the pressure-sensitive adhesive layer within the range of the present invention to satisfy a good drop impact resistance (peeling resistance upon drop impact), it is preferably 1.5 to 10% by weight. The proportion of the hydroxyl group-containing monomer is more preferably 2% by weight or more, still more preferably 3% by weight or more. The more the hydroxyl groups, the better the adhesion (to glass), the higher the elastic modulus at high temperature (80 ° C.) can be maintained, which is advantageous in preventing peeling in the reliability test. On the other hand, when the amount of the hydroxyl group-containing monomer is too large, the dielectric constant tends to be high, the pressure-sensitive adhesive layer becomes hard, and the adhesive strength may decrease, and the viscosity of the pressure-sensitive adhesive becomes too high The hydroxyl group-containing monomer is preferably 9% by weight or less, based on the total amount of monofunctional monomer components forming the (meth) acrylic polymer, because it may be gelled. % Or less is more preferable, and 7% by weight or less is more preferable.

  Moreover, as a copolymerization monomer in the said monofunctional monomer, functional group containing monomers other than the above-mentioned can be contained, For example, a carboxyl group containing monomer and the monomer which has a cyclic ether group are mentioned.

  As the carboxyl group-containing monomer, one having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a carboxyl group can be used without particular limitation. Examples of the carboxyl group-containing monomer include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid and the like. It can be used alone or in combination. Itaconic acid and maleic acid can use these anhydrides. Among these, acrylic acid and methacrylic acid are preferable, and acrylic acid is particularly preferable. In addition, a carboxyl group-containing monomer can be arbitrarily used for the monomer component used for manufacture of the (meth) acrylic-type polymer of this invention, On the other hand, it is not necessary to use a carboxyl group-containing monomer.

  As a monomer having a cyclic ether group, one having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a cyclic ether group such as an epoxy group or an oxetane group It can be used without particular limitation. Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether and the like. As the oxetane group-containing monomer, for example, 3-oxetanylmethyl (meth) acrylate, 3-methyl-oxetanylmethyl (meth) acrylate, 3-ethyl-oxetanylmethyl (meth) acrylate, 3-butyl-oxetanylmethyl (meth) acrylate And 3-hexyl-oxetanylmethyl (meth) acrylate. These can be used alone or in combination.

  The proportion of the carboxyl group-containing monomer and the monomer having a cyclic ether group is preferably 8% by weight or less, more preferably 5% by weight or less, based on the total amount of monofunctional monomers. When the pressure-sensitive adhesive layer of the present invention is used also in a mode in which the pressure-sensitive adhesive layer is brought into contact with a sensor film, it is preferable to adopt a mode in which no carboxyl group-containing monomer is used.

Further, as the copolymerizable monomer in the monofunctional monomer, ^{_{e.g., CH 2 = C (R 1}} ) COOR 2 ( wherein ^{R 1} is hydrogen or methyl, ^{R 2} is an alkyl group having 9 to 11 carbon atoms, carbon atoms And alkyl (meth) acrylates represented by 1 to 3 substituted alkyl groups and cyclic cycloalkyl groups).

Here, as a substituent of the C1-C3 substituted alkyl group as R ² , a C3-C8 aryl group or a C3-C8 aryloxy group is preferable . The aryl group is preferably, but not limited to, a phenyl group.

Examples of such a monomer represented by CH ₂ CC (R ¹ ) COOR ² include phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate and 3,3,5-trimethylcyclohexyl (Meth) acrylate, isobornyl (meth) acrylate and the like. These can be used alone or in combination.

The proportion of the (meth) acrylate represented by CH ₂ CC (R ¹ ) COOR ² is preferably 10% by weight or less based on the total amount of monofunctional monomers.

  Other copolymerization monomers include vinyl acetate, vinyl propionate, styrene, α-methylstyrene, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate, (meth) Glycol-based acrylic ester monomers such as methoxypolypropylene glycol acrylic acid; acrylic acid ester-based monomers such as (meth) acrylic acid tetrahydrofurfuryl, fluorine (meth) acrylate, silicone (meth) acrylate and 2-methoxyethyl acrylate; amide group-containing Monomers, amino group-containing monomers, imide group-containing monomers, vinyl ether monomers and the like can also be used.

  Furthermore, the silane type monomer containing a silicon atom, etc. are mentioned. Examples of silane monomers include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, 8-vinyloctyltrimethoxysilane 8-vinyloctyl triethoxysilane, 10-methacryloyloxydecyl trimethoxysilane, 10-acryloyloxydecyl trimethoxysilane, 10-methacryloyloxydecyl triethoxysilane, 10-acryloyloxydecyl triethoxysilane, and the like.

  The monomer component for forming the (meth) acrylic polymer of the present invention contains, in addition to the monofunctional monomer exemplified above, a polyfunctional monomer as needed to adjust the cohesion of the adhesive. be able to.

  The polyfunctional monomer is a monomer having at least two polymerizable functional groups having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group, for example, (poly) ethylene glycol di (meth) acrylate, (Poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,2-ethylene Glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate Ester compounds of polyhydric alcohol and (meth) acrylic acid such as allyl; allyl (meth) acrylate, vinyl (meth) acrylate, divinyl benzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl di (meth) acrylate, hexyl di (meta And the like. Among these, trimethylolpropane tri (meth) acrylate, hexanediol di (meth) acrylate, and dipentaerythritol hexa (meth) acrylate can be suitably used. The polyfunctional monomers can be used alone or in combination of two or more.

  The amount of the polyfunctional monomer used varies depending on the molecular weight, the number of functional groups, etc., but is preferably 3 parts by weight or less, more preferably 2 parts by weight or less, based on 100 parts by weight in total of the monofunctional monomers. 1 part by weight or less is more preferable. The lower limit value is not particularly limited, but is preferably 0 parts by weight or more, and more preferably 0.001 parts by weight or more. Adhesiveness can be improved by the usage-amount of a polyfunctional monomer being in the said range.

  The production of the (meth) acrylic polymer can be appropriately selected from known production methods such as solution polymerization, radiation polymerization such as ultraviolet (UV) polymerization, and various radical polymerization such as bulk polymerization and emulsion polymerization. Further, the (meth) acrylic polymer to be obtained may be any of a random copolymer, a block copolymer, a graft copolymer and the like.

  Moreover, in the present invention, a partially polymerized product of the monomer component can also be suitably used.

  When the (meth) acrylic polymer is produced by radical polymerization, polymerization can be carried out by appropriately adding a polymerization initiator, a chain transfer agent, an emulsifier and the like used for radical polymerization to the monomer component. The polymerization initiator, chain transfer agent, emulsifier and the like used for the radical polymerization are not particularly limited and can be appropriately selected and used. The weight average molecular weight of the (meth) acrylic polymer can be controlled by the amount of the polymerization initiator and the chain transfer agent used, and the reaction conditions, and the amount used can be appropriately adjusted according to the type of these.

  For example, in solution polymerization etc., ethyl acetate, toluene etc. are used as a polymerization solvent, for example. As a specific example of solution polymerization, the reaction is carried out under a stream of an inert gas such as nitrogen, usually with a polymerization initiator added, at about 50 to 70 ° C., for about 5 to 30 hours.

  As a thermal polymerization initiator used for solution polymerization etc., for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis (2 -Methylpropionic acid) dimethyl, 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis [2- (5-Methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) disulfate, 2,2'-azobis (N, N'-dimethylene isobutyl Amidine), 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (VA-057, Wako Pure Chemical Industries, Ltd. Azo initiators such as potassium persulfate, ammonium persulfate, di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec -Butyl peroxy dicarbonate, t-butyl peroxy neodecanoate, t-hexyl peroxy pivalate, t-butyl peroxy pivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1 3,3-Tetramethylbutylperoxy-2-ethylhexanoate, di (4-methylbenzoyl) peroxide, dibenzoylperoxide, t-butylperoxyisobutyrate, 1,1-di (t-hexyl) Peroxy) cyclohexane, t-butyl hydroperoxide, hydrogen peroxide etc. May be mentioned, for example, halide initiators, combinations of persulfates and sodium bisulfite, redox initiators such as combinations of peroxides and sodium ascorbate and combinations of reducing agents with peroxides, etc. It is not limited.

  The polymerization initiator may be used alone or in combination of two or more, but it is preferably about 1 part by weight or less based on 100 parts by weight of the total amount of the monomer components. The amount is preferably about 0.005 to 1 part by weight, and more preferably about 0.02 to 0.5 part by weight.

  When 2,2′-azobisisobutyronitrile is used as the polymerization initiator, the amount of the polymerization initiator used is about 0.2 parts by weight or less based on 100 parts by weight of the total amount of the monomer components. Is preferable, and it is more preferable to set it to about 0.06 to 0.2 parts by weight.

  Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, 2,3-dimercapto-1-propanol and the like. The chain transfer agent may be used alone or as a mixture of two or more, but the total content is 0.3 parts by weight with respect to 100 parts by weight of the total amount of the monomer components. Less than or equal to.

  Moreover, as an emulsifier used when carrying out the emulsion polymerization, for example, anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecyl benzene sulfonate, ammonium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, etc., polyoxy Nonionic emulsifiers, such as ethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene polyoxypropylene block polymer, etc. are mentioned. These emulsifiers may be used alone or in combination of two or more.

  Furthermore, as a reactive emulsifier, as an emulsifier into which a radical polymerizable functional group such as propenyl group or allyl ether group has been introduced, specifically, for example, Aqualon HS-10, HS-20, KH-10, BC-05 BC-10, BC-20 (all from Dai-ichi Kogyo Seiyaku Co., Ltd.), Adekaria Soap SE10N (manufactured by Adeka), and the like. The amount of the emulsifier used is preferably 5 parts by weight or less based on 100 parts by weight of the total amount of the monomer components.

  Moreover, when manufacturing the said (meth) acrylic-type polymer by radiation polymerization, it can superpose | polymerize by irradiating radiation, such as an electron beam and an ultraviolet-ray (UV), to the said monomer component. Among these, ultraviolet polymerization is preferable. Hereinafter, ultraviolet polymerization which is a preferable embodiment in radiation polymerization will be described.

  When the ultraviolet polymerization is performed, it is preferable that the monomer component contains a photopolymerization initiator from the advantage that the polymerization time can be shortened. Therefore, when performing UV polymerization, for example, a monomer component containing a monofunctional monomer component containing the alkyl (meth) acrylate (A) and (B) and / or a partial polymer of the monomer component, a UV absorber, and It is preferable to form by ultraviolet-ray polymerizing the ultraviolet curable acrylic adhesive composition containing a photoinitiator. The pressure-sensitive adhesive layer formed by UV-polymerizing the above-mentioned ultraviolet-curable acrylic pressure-sensitive adhesive composition can also be formed with a thickness of 150 μm or more, and a wide-thickness pressure-sensitive adhesive layer can be formed. preferable.

  The photopolymerization initiator is not particularly limited, but preferably contains a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more. In the case where the pressure-sensitive adhesive composition contains a UV absorber, when UV polymerization is carried out, the UV absorber is absorbed by the UV absorber so that sufficient polymerization can not be achieved. However, a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more is preferable because it can be sufficiently polymerized although it contains an ultraviolet light absorber.

  As the photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more, bis (2,4,6-trimethyl benzoyl) -phenyl phosphine oxide (Irgacure 819, manufactured by BASF), 2,4,6-trimethyl benzoyl- Diphenyl-phosphine oxide (LUCIRIN TPO, manufactured by BASF) etc. can be mentioned.

  The photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more may be used alone or in combination of two or more.

  The addition amount of the photopolymerization initiator (A) having an absorption band at the wavelength of 400 nm or more is not particularly limited, but is preferably smaller than the addition amount of the ultraviolet light absorber described later, (meth) The amount is preferably 2 parts by weight or less, more preferably about 0.005 to 1 part by weight, and preferably 0.02 to 0.8 parts by weight with respect to 100 parts by weight of the monofunctional monomer component forming the acrylic polymer. More preferably, When the addition amount of the photopolymerization initiator (A) is in the above-mentioned range, ultraviolet polymerization can be sufficiently advanced, which is preferable.

  Further, the photopolymerization initiator can contain a photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm. The photopolymerization initiator (B) is not particularly limited as long as it generates radicals by ultraviolet rays and starts photopolymerization, and has an absorption band at a wavelength of less than 400 nm, and usually used photopolymerization Any initiator can be suitably used. For example, benzoin ether type photopolymerization initiator, acetophenone type photopolymerization initiator, α-ketol type photopolymerization initiator, photoactive oxime type photopolymerization initiator, benzoin type photopolymerization initiator, benzyl type photopolymerization initiator, benzophenone A system photopolymerization initiator, a ketal photopolymerization initiator, a thioxanthone photopolymerization initiator, an acyl phosphine oxide photopolymerization initiator, and the like can be used.

  Specifically, as benzoin ether photopolymerization initiators, for example, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane- 1-one, anisole methyl ether etc. are mentioned.

  Examples of acetophenone photopolymerization initiators include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, 4-t-butyldichloroacetophenone Etc.

  Examples of α-ketol photopolymerization initiators include 2-methyl-2-hydroxypropiophenone, 1- [4- (2-hydroxyethyl) phenyl] -2-hydroxy-2-methylpropan-1-one, etc. Can be mentioned.

  Examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,2-propanedione-2- (O-ethoxycarbonyl) -oxime and the like.

  Examples of benzoin photopolymerization initiators include benzoin.

  As a benzyl type photoinitiator, a benzyl etc. are contained, for example.

  The benzophenone series photoinitiators include, for example, benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexyl phenyl ketone and the like.

  The ketal photopolymerization initiators include benzyl dimethyl ketal and the like.

  Thioxanthone photopolymerization initiators include, for example, thioxanthone, 2-chlorothioxanthone, 2-methyl thioxanthone, 2,4-dimethyl thioxanthone, isopropyl thioxanthone, 2,4-dichloro thioxanthone, 2,4-diethyl thioxanthone, 2,4- -Including diisopropyl thioxanthone, dodecyl thioxanthone and the like.

  The acyl phosphine oxide photopolymerization initiators include, for example, 2,4,6-trimethyl benzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethyl benzoyl) -phenyl phosphine oxide and the like.

  The photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm can be used alone or in combination of two or more. The photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm can be added as long as the effects of the present invention are not impaired, but the addition amount is a monofunctional that forms a (meth) acrylic polymer The amount is preferably about 0.005 to 0.5 parts by weight, and more preferably about 0.02 to 0.2 parts by weight with respect to 100 parts by weight of the base monomer component.

  In the present invention, when the monomer component is subjected to ultraviolet polymerization, a photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm is first added to the monomer component, and ultraviolet light is irradiated to partially polymerize. It is preferable to perform ultraviolet polymerization by adding a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more and an ultraviolet light absorber to the partial polymer (prepolymer composition) of the monomer component. When adding the photopolymerization initiator (A) having an absorption band at the wavelength of 400 nm or more to the partially polymerized product (prepolymer composition) of the monomer component partially polymerized by ultraviolet irradiation, the photopolymerization initiation It is preferable to add the agent after dissolving it in the monomer.

  The weight average molecular weight of the (meth) acrylic polymer of the present invention is preferably 400,000 to 3,000,000, and more preferably 600,000 to 2,500,000. By making the weight average molecular weight larger than 400,000, it is possible to satisfy the durability of the pressure-sensitive adhesive layer or to suppress the cohesion of the pressure-sensitive adhesive layer to form adhesive residue. On the other hand, when the weight average molecular weight is larger than 3,000,000, the bondability and the adhesion tend to be lowered. Furthermore, in the solution system, the viscosity of the pressure sensitive adhesive may be too high, which may make coating difficult. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated by polystyrene conversion. In addition, about the (meth) acrylic-type polymer obtained by radiation polymerization, molecular weight measurement is difficult.

<Measurement of weight average molecular weight>
The weight average molecular weight of the obtained (meth) acrylic polymer was measured by GPC (gel permeation chromatography). The sample was dissolved in tetrahydrofuran to make a 0.1% by weight solution, which was allowed to stand overnight, and then filtrated through a 0.45 μm membrane filter was used.
・ Analyzer: HLC-8120 GPC manufactured by Tosoh Corporation
・ Column: Tosoh Corporation,: GM7000HXL + GMHXL + GMHXL
・ Column size; each 7.8mmφ × 30cm in total 90cm
Eluent: tetrahydrofuran (concentration 0.1% by weight)
・ Flow rate: 0.8 ml / min
・ Inlet pressure: 1.6MPa
・ Detector: Differential refractometer (RI)
・ Column temperature: 40 ° C
Injection volume: 100 μl
Eluent: Tetrahydrofuran Detector: Differential refractometer Standard sample: Polystyrene

(2) UV Absorber The UV absorber is not particularly limited. For example, triazine UV absorber, benzotriazole UV absorber, benzophenone UV absorber, oxybenzophenone UV absorber, salicylic acid ester UV An absorber, a cyanoacrylate type ultraviolet absorber, etc. can be mentioned, These can be used individually by 1 type or in combination of 2 or more types. Among these, triazine-based UV absorbers and benzotriazole-based UV absorbers are preferable, triazine-based UV absorbers having two or less hydroxyl groups in one molecule, and benzo having one benzotriazole skeleton in one molecule. At least one UV absorber selected from the group consisting of triazole UV absorbers, which has good solubility in the monomers used to form the acrylic pressure-sensitive adhesive composition, and a wavelength near 380 nm Is preferred because of its high ability to absorb ultraviolet light.

  Specifically as a triazine type ultraviolet absorber having two or less hydroxyl groups in one molecule, 2,4-bis-[{4- (4-ethylhexyloxy) -4-hydroxy} -phenyl] -6 -(4-Methoxyphenyl) -1,3,5-triazine (Tinosorb S, manufactured by BASF), 2,4-bis [2-hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) -1,3,5-Triazine (TINUVIN 460, manufactured by BASF), 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -5-hydroxyphenyl Of [(C10-C16 (mainly C12-C13) alkyloxy) methyl] oxirane (TINUVIN 400, manufactured by BASF), 2- [4, 6-bis (2, -Dimethylphenyl) -1,3,5-triazin-2-yl] -5- [3- (dodecyloxy) -2-hydroxypropoxy] phenol), 2- (2,4-dihydroxyphenyl) -4,6 -Reaction product of bis- (2,4-dimethylphenyl) -1,3,5-triazine and (2-ethylhexyl) -glycidic ester (TINUVIN 405, manufactured by BASF), 2- (4,6-diphenyl-1) , 3,5-Triazin-2-yl) -5-[(hexyl) oxy] -phenol (TINUVIN 1577, manufactured by BASF), 2- (4,6-diphenyl-1,3,5-triazin-2-yl)- 5- [2- (2-ethylhexanoyloxy) ethoxy] -phenol (ADK STAB LA46, manufactured by ADEKA), 2- (2-hydroxy-4- [4 - octyloxycarbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl) -1,3,5-triazine (TINUVIN 479, manufactured by BASF), and the like.

  Moreover, as a benzotriazole type ultraviolet absorber having one benzotriazole skeleton in one molecule, 2- (2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-Tetramethylbutyl) phenol (TINUVIN 928, manufactured by BASF), 2- (2-hydroxy-5-tert-butylphenyl) -2H-benzotriazole (TINUVIN PS, manufactured by BASF), benzene Ester compounds of propanoic acid and 3- (2H-benzotriazol-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy (C7-9 side chain and straight chain alkyl) (TINUVIN 384-2, BASF Product), 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenyl) Ethyl) phenol (TINUVIN 900, manufactured by BASF), 2- (2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) ) Reaction products of phenol (TINUVIN 928, from BASF), methyl-3- (3- (2H-benzotriazol-2-yl) -5-t-butyl-4-hydroxyphenyl) propionate / polyethylene glycol 300 (TINUVIN 1130, BASF), 2- (2H-benzotriazol-2-yl) -p-cresol (TINUVIN P, BASF), 2 (2H-benzotriazol-2-yl) -4-6-bis (1-methyl-) 1-phenylethyl) phenol (TINUVIN 234, manufactured by BASF), 2- [5- (2H) -benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol (TINUVIN 326, manufactured by BASF), 2- (2H-benzotriazol-2-yl) -4,6-di -Tert-pentylphenol (TINUVIN 328, manufactured by BASF), 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol (TINUVIN 329, manufactured by BASF), methyl 3 Reaction product of (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate and polyethylene glycol 300 (TINUVIN 213, manufactured by BASF), 2- (2H-benzotriazole) -2-yl) -6-dodecyl-4-methylphenol (TI NUVIN 571 (manufactured by BASF), 2- [2-hydroxy-3- (3,4,5,6-tetrahydrophthalimido-methyl) -5-methylphenyl] benzotriazole (Sumisorb 250, manufactured by Sumitomo Chemical Co., Ltd.), etc. It can be mentioned.

  Further, examples of the benzophenone based ultraviolet absorber (benzophenone based compound) and the oxybenzophenone based ultraviolet absorber (oxybenzophenone based compound) include, for example, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, and 2-hydroxy. -4-methoxybenzophenone-5-sulfonic acid (anhydrous and trihydrate), 2-hydroxy-4-octyloxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 4-benzyloxy-2-hydroxybenzophenone, 2, 2 ′, 4,4′-tetrahydroxybenzophenone, 2,2′-dihydroxy-4,4-dimethoxybenzophenone and the like can be mentioned.

  Moreover, as said salicylic acid ester type ultraviolet absorber (salicylic acid ester type compound), for example, phenyl-2-acryloyloxybenzoate, phenyl-2-acryloyloxy-3-methylbenzoate, phenyl-2-acryloyloxy -4-Methyl benzoate, phenyl-2-acryloyloxy-5-methyl benzoate, phenyl-2-acryloyloxy-3-methoxy benzoate, phenyl 2-hydroxy benzoate, phenyl 2-hydroxy -3-Methylbenzoate, phenyl-2-hydroxy-4methylbenzoate, phenyl-2-hydroxy-5-methylbenzoate, phenyl 2-hydroxy-3-methoxybenzoate, 2,4-di-tert -Butylphenyl-3,5-di-tert-bu And the like-4-hydroxybenzoate (TINUVIN120, manufactured by BASF).

  Examples of the cyanoacrylate ultraviolet absorber (cyanoacrylate compound) include alkyl-2-cyanoacrylate, cycloalkyl-2-cyanoacrylate, alkoxyalkyl-2-cyanoacrylate, alkenyl-2-cyanoacrylate, and alkynyl- 2-cyanoacrylate etc. can be mentioned.

  The maximum absorption wavelength of the absorption spectrum of the ultraviolet absorber is preferably in the wavelength range of 300 to 400 nm, and more preferably in the wavelength range of 320 to 380 nm. The method of measuring the maximum absorption wavelength is the same as the method of measuring the dye-based compound described later.

  Although the said ultraviolet absorber may be used independently and may be used in mixture of 2 or more types, the content as a whole is a monofunctional monomer component which forms a (meth) acrylic-type polymer. The amount is preferably about 0.1 to 5 parts by weight, and more preferably about 0.5 to 3 parts by weight with respect to 100 parts by weight. By setting the amount of the ultraviolet absorber to be in the above range, the ultraviolet absorbing function of the pressure-sensitive adhesive layer can be sufficiently exhibited, and when ultraviolet polymerization is performed, it is preferable because it does not interfere with the polymerization.

(3) Dye Compound Furthermore, the pressure-sensitive adhesive composition of the present invention can contain a dye compound in which the maximum absorption wavelength of the absorption spectrum is in a wavelength range of 380 to 430 nm. Here, the maximum absorption wavelength means an absorption maximum wavelength showing the maximum absorbance among a plurality of absorption maxima in the spectral absorption spectrum in the wavelength region of 300 to 460 nm. .

  The dye compound used in the present invention is not particularly limited as long as it is a compound having the maximum absorption wavelength of the absorption spectrum in the wavelength range of 380 to 430 nm. The maximum absorption wavelength of the absorption spectrum of the dye compound is more preferably in the wavelength range of 380 to 420 nm. In the present invention, by using such a dye compound in combination with the ultraviolet absorber, light in a region (wavelength 380 nm to 430 nm) which does not affect light emission of the organic EL element can be sufficiently absorbed, and The light emitting region (longer wavelength than 430 nm) of the organic EL element can be sufficiently transmitted, and as a result, deterioration of the organic EL element due to external light can be suppressed. The dye compound is not particularly limited as long as it has the above-mentioned wavelength characteristics, but a material having neither fluorescence nor phosphorescence performance (photoluminescence) which does not inhibit the display performance of the organic EL element is preferable.

The half-width of the dye compound is not particularly limited, but is preferably 80 nm or less, more preferably 5 to 70 nm, and still more preferably 10 to 60 nm. When the full width at half maximum of the dye compound is in the above range, it is possible to sufficiently transmit light in a region that does not affect the light emission of the organic EL element while transmitting sufficient light at wavelengths longer than 430 nm. Because it is preferable. In addition, the measuring method of a half value width is based on the method as described below.
<Method of measuring half width>
The full width at half maximum of the dye compound was measured from the transmission absorption spectrum of the solution of the dye compound under the following conditions using an ultraviolet-visible spectrophotometer (U-4100, manufactured by Hitachi High-Tech Science Co., Ltd.). From the spectrum measured by adjusting the concentration so that the absorbance at the maximum absorption wavelength is 1.0, the distance (full width at half maximum) between the two points at 50% of the peak value is taken as the half width of the dye compound .
(Measurement condition)
Solvent: toluene or chloroform Cell: quartz cell Optical path length: 10 mm

  The dye compound may be any compound as long as it has a maximum absorption wavelength of 380 to 430 nm in the absorption spectrum, and the structure thereof is not particularly limited. Examples of the dye compound include organic dye compounds and inorganic dye compounds. Among them, organic dyes are preferred from the viewpoint of maintaining dispersibility in resin components such as a base polymer and transparency. Compounds are preferred.

  Examples of the organic dye compounds include azomethine compounds, indole compounds, cinnamic acid compounds, pyrimidine compounds and porphyrin compounds.

  As the organic dye compound, commercially available ones can be suitably used. Specifically, as the indole compound, BONASORB UA3911 (trade name, maximum absorption wavelength of absorption spectrum: 398 nm, half width: 48 nm, made by Orient Chemical Industry Co., Ltd., BONASORB UA3912 (trade name, maximum absorption wavelength of absorption spectrum: 386 nm, half bandwidth: 53 nm, made by Orient Chemical Industry Co., Ltd.), SOM as a cinnamic acid compound -5-0106 (trade name, maximum absorption wavelength of absorption spectrum: 416 nm, half width: 50 nm, made by Orient Chemical Industries Ltd.), and as a porphyrin compound, FDB-001 (trade name, maximum absorption wavelength of absorption spectrum) : 420 nm, half bandwidth: 14 nm, Yamada Chemical Industry Co., Ltd. Can be

  The dye compounds may be used alone or in combination of two or more, but the total content is a monofunctional monomer component 100 forming a (meth) acrylic polymer. It is preferably about 0.01 to 10 parts by weight, and more preferably about 0.02 to 5 parts by weight with respect to the parts by weight. By setting the addition amount of the dye compound in the above range, light of a region which does not affect light emission of the organic EL element can be sufficiently absorbed, and by using the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition, It is preferable because deterioration of the organic EL element can be suppressed.

(4) Silane Coupling Agent Furthermore, the pressure-sensitive adhesive composition of the present invention can contain a silane coupling agent. The compounding amount of the silane coupling agent is preferably 3 parts by weight or less, preferably 1 part by weight or less, with respect to 100 parts by weight of the monofunctional monomer component forming the (meth) acrylic polymer. .01 to 1 part by weight is more preferable, and 0.02 to 0.6 part by weight is further preferable.

  Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4 epoxycyclohexyl) Epoxy group-containing silane coupling agent such as ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,1 Amino group-containing silane coupling agents such as 3-dimethylbutylidene) propylamine, N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane Meta) Acrylic group containing silane Coupling agent, 3-isocyanate propyltriethoxysilane isocyanate group-containing silane coupling agents such as and the like.

(5) Crosslinking agent The pressure-sensitive adhesive composition of the present invention can contain a crosslinking agent. As a crosslinking agent, an isocyanate type crosslinking agent, an epoxy type crosslinking agent, a silicone type crosslinking agent, an oxazoline type crosslinking agent, an aziridine type crosslinking agent, a silane type crosslinking agent, an alkyl etherified melamine type crosslinking agent, a metal chelate type crosslinking agent, Crosslinkers such as oxides are included. The crosslinking agents can be used alone or in combination of two or more. Among these, an isocyanate type crosslinking agent is preferably used.

  Although the said crosslinking agent may be used individually by 1 type and may be used in mixture of 2 or more types, the content as a whole is a monofunctional monomer which forms a (meth) acrylic-type polymer. The amount is preferably 5 parts by weight or less, more preferably 0.01 to 5 parts by weight, still more preferably 0.01 to 4 parts by weight, and more preferably 0.02 to 3 parts by weight with respect to 100 parts by weight of the component. Particularly preferred.

  An isocyanate type crosslinking agent refers to a compound having two or more isocyanate groups (including an isocyanate regenerated functional group in which an isocyanate group is temporarily protected by a blocking agent or quantification or the like) in one molecule. As an isocyanate type crosslinking agent, aromatic isocyanates, such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates, such as isophorone diisocyanate, aliphatic isocyanates, such as hexamethylene diisocyanate, etc. are mentioned.

  More specifically, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, cycloaliphatic diisocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate, 2,4-tolylene diisocyanate, Aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylene polyphenylisocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) ), Trimethylolpropane / hexamethylene diisocyanate trimer adduct (trade name: Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.), hexamethylene Isocyanate adduct of isocyanurate of isocyanate (trade name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane adduct of xylylene diisocyanate (trade name: D110N, manufactured by Mitsui Chemicals, Inc.), hexa Trimethylolpropane adduct of methylene diisocyanate (trade name: D160N, manufactured by Mitsui Chemicals, Inc.); polyether polyisocyanate, polyester polyisocyanate, adducts of these with various polyols, isocyanurate bond, buret bond, The polyisocyanate etc. which were polyfunctionalized by the allophanate coupling etc. can be mentioned.

(6) Other Additives The pressure-sensitive adhesive composition of the present invention may contain, in addition to the components described above, appropriate additives depending on the application. For example, tackifier (for example, solid, semi-solid or liquid at room temperature consisting of rosin derivative resin, polyterpene resin, petroleum resin, oil-soluble phenolic resin, etc.); Filler such as hollow glass balloon; Plasticizer; Inhibitors; light stabilizers (HALS); antioxidants etc. may be mentioned. Furthermore, it is preferable to contain a rust inhibitor (benzotriazole compound etc.) for the purpose of suppressing corrosion of a conductive metal, lead wiring and the like. These additives are preferably contained in an amount of 1 part by weight or less with respect to 100 parts by weight of the monofunctional monomer component.

  In the present invention, the pressure-sensitive adhesive composition is preferably adjusted to a viscosity suitable for an operation of coating or the like on a substrate. The adjustment of the viscosity of the pressure-sensitive adhesive composition is performed, for example, by adding various polymers such as a thickening additive or a polyfunctional monomer, or partially polymerizing monomer components in the pressure-sensitive adhesive composition. The partial polymerization may be carried out before or after addition of various polymers such as thickening additives and polyfunctional monomers. The viscosity of the above-mentioned pressure-sensitive adhesive composition varies depending on the amount of the additive and the like, so the polymerization rate in the case of partially polymerizing the monomer component in the pressure-sensitive adhesive composition can not be determined uniquely. Is preferably, 3 to 20% is more preferable, and 5 to 15% is more preferable. If it exceeds 20%, the viscosity becomes too high, which makes it difficult to apply to a substrate.

2. Pressure-Sensitive Adhesive Layer for Organic EL Display Device The pressure-sensitive adhesive layer for an organic EL display device of the present invention is formed from the pressure-sensitive adhesive composition for an organic EL display device.

  The thickness of the pressure-sensitive adhesive layer of the present invention is preferably 12 μm or more, more preferably 50 μm or more, and further preferably 100 μm or more from the viewpoint of securing the function of absorbing light with a wavelength of less than 430 nm. Preferably, it is particularly preferably 150 μm or more. The upper limit of the thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 1 mm or less, more preferably 300 μm or less, and still more preferably 250 μm or less. When the thickness of the pressure-sensitive adhesive layer exceeds 1 mm, the transmission of ultraviolet light becomes difficult, and it takes time to polymerize the monomer component, and problems occur in processability, winding up in steps and transportability, and productivity is poor. Not desirable because

  The pressure-sensitive adhesive layer of the present invention has a tan δ peak value (Tg) of -20 ° C to -5 ° C when dynamic viscoelasticity is measured at a frequency of 1 Hz, preferably -19 ° C to -6 ° C, more preferably Is -18 ° C to -7 ° C. When the Tg is higher than -5 ° C, the pressure-sensitive adhesive layer is hard and lacks flexibility, and therefore, the peeling resistance at the time of a drop impact can not be satisfied. On the other hand, when the Tg is lower than -20 ° C., the film becomes too soft and it becomes difficult to secure the elastic modulus at high temperature.

  The pressure-sensitive adhesive layer of the present invention has a transmittance of 10% or less at a wavelength of 380 nm and a transmittance of 85% or more at a wavelength of 450 nm.

  The transmittance at a wavelength of 380 nm of the pressure-sensitive adhesive layer is preferably 5% or less, more preferably 2% or less. The light of the area | region which does not influence light emission of an organic EL element as the transmittance | permeability of an adhesive layer is the said range can fully be absorbed, and degradation of an organic EL element can be suppressed.

  The transmittance at a wavelength of 450 nm of the pressure-sensitive adhesive layer is preferably 88% or more, preferably 89% or more, and more preferably 90% or more. When the transmittance of the pressure-sensitive adhesive layer is in the above range, light can be sufficiently transmitted in the light emitting region (longer wavelength side than 430 nm) of the organic EL element, and the organic EL using the pressure-sensitive adhesive layer The display device can emit sufficient light.

  Further, the pressure-sensitive adhesive layer of the present invention can sufficiently absorb light in a region which does not affect light emission of the organic EL device by having the transmittance, and the light emitting region (longer than 430 nm of the organic EL device) The wavelength side can be sufficiently transmitted, and deterioration of the organic EL element due to external light can be suppressed.

The pressure-sensitive adhesive layer of the present invention has a total light transmittance of 85% or more. The total light transmittance is preferably 88% or more, preferably 89% or more, and more preferably 90% or more. The haze is 0 to 1%, preferably 0.8% or less, and more preferably 0.6% or less. The pressure-sensitive adhesive layer has high transparency because the total light transmittance and the haze are in the above ranges.
The pressure-sensitive adhesive layer of the present invention preferably has the total light transmittance and the haze satisfying the above range regardless of the thickness, and the thickness of the pressure-sensitive adhesive layer preferably satisfies the above range by 12 to 250 μm, and further 12 μm. It is particularly preferable to satisfy the above range in the range of 1 mm.

  The pressure-sensitive adhesive layer of the present invention preferably has a dielectric constant at a frequency of 100 kHz of 3.5 or less, more preferably 3.3 or less, still more preferably 3.2 or less, and still more preferably 3.0 It is below.

  The gel fraction of the pressure-sensitive adhesive layer of the present invention is not particularly limited, but is preferably 50 to 95% by weight. The gel fraction is more preferably 75% or more, further preferably 85% or more. By adjusting the gel fraction of the pressure-sensitive adhesive layer to the above range, the cohesion of the pressure-sensitive adhesive layer can be secured, which is preferable in terms of processability and handling.

  Further, the pressure-sensitive adhesive layer of the present invention has a 180 degree peel adhesive strength (peeling speed of 300 mm / min) against alkali-free glass of 7 N / 20 mm or more to prevent peeling of the film in the reliability test or drop impact. It is preferable from the point of prevention of peeling. The adhesive strength is preferably 8 N / 20 mm or more, and more preferably 10 N / 20 mm or more. On the other hand, the adhesive strength is preferably 30 N / 20 mm or less, more preferably 28 N / 20 mm or less, from the viewpoint of adhesion of the blade to the blade during processing, making processing difficult and contaminating the generated adhesive fragments.

  The method of forming the pressure-sensitive adhesive layer is not particularly limited, and the pressure-sensitive adhesive layer can be formed by a method generally used in the present field. Specifically, the pressure-sensitive adhesive composition is coated on at least one surface of a substrate, and a coated film formed from the pressure-sensitive adhesive composition is dried and formed, or an active energy ray such as ultraviolet light is irradiated. Can be formed.

  It does not specifically limit as said base material, For example, various base materials, such as a release film and a transparent resin film base material, and the polarizing film mentioned later can also be used suitably as a base material. A conductive layer may be provided on the side of the base on which the pressure-sensitive adhesive layer is provided and / or on the back side for the purpose of preventing charging.

  In addition, a pressure-sensitive adhesive layer formed on a release film (separator) is further provided with a release film (separator) as a sheet-like material, release film (separator) / pressure-sensitive adhesive layer / release film (separator), It can be used in the form of

  As a constituent material of the release film, for example, resin film such as polyethylene, polypropylene, polyethylene terephthalate, polyester film, porous material such as paper, cloth, non-woven fabric, net, foam sheet, metal foil, and laminate thereof Although an appropriate thin leaf etc. can be mentioned, a resin film is used suitably from the point which is excellent in surface smoothness.

  As the resin film, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene film -A vinyl acetate copolymer film etc. are mentioned.

  The thickness of the release film is usually 5 to 200 μm, and preferably about 5 to 100 μm. The release film may be, if necessary, a release agent of silicone type, fluorine type, long chain alkyl type or fatty acid amide type, silica powder etc, release treatment and antifouling treatment, coating type, kneading type, It is also possible to carry out an antistatic treatment such as a deposition type. In particular, the releasability from the pressure-sensitive adhesive layer can be further enhanced by appropriately performing release treatment such as silicone treatment, long chain alkyl treatment, fluorine treatment and the like on the surface of the release film.

  The transparent resin film substrate is not particularly limited, but various resin films having transparency are used. The said resin film is formed of the film of one layer. For example, as the material, polyester resin such as polyethylene terephthalate and polyethylene naphthalate, acetate resin, polyether sulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, (meth) acrylic resin Polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyarylate resin, polyphenylene sulfide resin and the like can be mentioned. Among these, polyester resins, polyimide resins and polyethersulfone resins are particularly preferable.

  The thickness of the film substrate is preferably 15 to 200 μm, and more preferably 25 to 188 μm.

  The method for applying the pressure-sensitive adhesive composition onto the substrate may be roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain Well-known appropriate methods, such as a coat, a lip coat, a die coater, can be used, and it does not restrict | limit in particular.

  When the pressure-sensitive adhesive layer is formed by drying a coating film formed of the pressure-sensitive adhesive composition, the drying conditions (temperature, time) are not particularly limited, and the composition of the pressure-sensitive adhesive composition Although it can set suitably by a density | concentration etc., for example, it is about 60-170 degreeC, Preferably it is 60-150 degreeC, 1 to 60 minutes, Preferably it is 2 to 30 minutes.

When the pressure-sensitive adhesive composition is an ultraviolet-curable pressure-sensitive adhesive composition and the coating film formed from the ultraviolet-curable pressure-sensitive adhesive composition is formed by irradiating the ultraviolet light, the illuminance of the ultraviolet light to be irradiated is 5 mW /. cm ² or more is preferred. When the illuminance of the ultraviolet light is less than 5 mW / cm ² , the polymerization reaction time may be prolonged and the productivity may be poor. In addition, as for the illumination intensity of the said ultraviolet-ray, 200 mW / cm < ² > or less is preferable. When the illuminance of the ultraviolet light exceeds 200 mW / cm ² , the photopolymerization initiator is rapidly consumed, so that the polymer may be reduced in molecular weight, and in particular, the holding power at high temperatures may be reduced. Further, the integrated quantity of ultraviolet light ^is preferably ^{100mJ / cm 2 ~5000mJ / cm 2} .

  The ultraviolet lamp used in the present invention is not particularly limited, but an LED lamp is preferable. Since the LED lamp has a lower heat release than other ultraviolet lamps, the temperature during polymerization of the adhesive layer can be suppressed. Therefore, it is possible to prevent the lowering of the molecular weight of the polymer, and to prevent the lowering of the cohesion of the pressure-sensitive adhesive layer, and to enhance the holding power at high temperature when forming the pressure-sensitive adhesive sheet. It is also possible to combine multiple ultraviolet lamps. In addition, it is possible to intermittently irradiate ultraviolet light and provide a light period in which the ultraviolet light is irradiated and a dark period in which the ultraviolet light is not irradiated.

  In the present invention, the final polymerization rate of the monomer component in the ultraviolet-curable pressure-sensitive adhesive composition is preferably 90% or more, more preferably 95% or more, and still more preferably 98% or more.

  In the present invention, the peak wavelength of the ultraviolet light irradiated to the ultraviolet-curable pressure-sensitive adhesive composition is preferably in the range of 200 to 500 nm, and more preferably in the range of 300 to 450 nm. When the peak wavelength of ultraviolet light exceeds 500 nm, the photopolymerization initiator may not be decomposed and the polymerization reaction may not start. In addition, when the peak wavelength of ultraviolet light is less than 200 nm, polymer chains may be cut, and adhesion properties may be degraded.

  Since the reaction is inhibited by oxygen in the air, a release film or the like is formed on a coating film formed of an ultraviolet-curable acrylic pressure-sensitive adhesive composition to block oxygen, or a photopolymerization reaction is performed using nitrogen It is preferable to carry out under an atmosphere. As a release film, the above-mentioned thing can be mentioned. In addition, when a release film is used, the said release film can be used as a separator of the polarizing film with an adhesive layer as it is.

  Moreover, when the ultraviolet curable adhesive composition used by this invention contains a photoinitiator (B), the monomer component containing an alkyl (meth) acrylate and the said photoinitiator (B) (" The composition containing “additional polymerization initiator” is irradiated with ultraviolet light to form a partial polymer of the monomer component, and the partial polymer of the monomer component is a UV absorber, and a wavelength of 400 nm or more. It is preferable to prepare a UV-curable pressure-sensitive adhesive composition by adding a photopolymerization initiator (A) (sometimes referred to as "post-addition polymerization initiator") having an absorption band. The polymerization rate of the partially polymerized product is preferably about 20% or less, more preferably about 3 to 20%, and still more preferably about 5 to 15%. The irradiation conditions of the ultraviolet light are as described above.

  As mentioned above, when forming an adhesive layer from the ultraviolet curing adhesive composition containing a photoinitiator (B), the polymerization rate of a monomer component is raised by superposing | polymerizing in two steps as mentioned above. It is possible to improve the ultraviolet absorbing function of the finally produced pressure-sensitive adhesive layer.

3. Polarizing film with pressure-sensitive adhesive layer for organic EL display device The polarizing film with pressure-sensitive adhesive layer for an organic EL display device of the present invention is characterized by having a polarizing film and the pressure-sensitive adhesive layer for the organic EL display device.

  As the pressure-sensitive adhesive layer for an organic EL display device, those described above can be suitably used. When the pressure-sensitive adhesive layer is formed on a substrate other than the polarizing film, the pressure-sensitive adhesive layer can be attached to the polarizing film and transferred. Moreover, the said release film can be used as a separator of the polarizing film with an adhesive layer as it is, and the simplification in a process surface can be performed.

  Although it does not specifically limit as said polarizing film, What has a transparent protective film in at least single side | surface of a polarizer and the said polarizer can be mentioned.

(1) Polarizer The polarizer is not particularly limited, and various types of polarizers can be used. As a polarizer, for example, a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or an ethylene / vinyl acetate copolymer-based partially saponified film, dichroism of iodine or a dichroic dye Examples thereof include those obtained by adsorbing a substance and uniaxially stretched, and dehydrated products of polyvinyl alcohol and dehydrochlorinated products of polyvinyl chloride such as polyene-based oriented films. Among these, a polarizer made of a polyvinyl alcohol film and a dichroic substance such as iodine is preferable. Although the thickness in particular of these polarizers is not restrict | limited, Generally it is about 5-80 micrometers.

  The polarizer which dye | stained the polyvinyl alcohol-type film with iodine, and uniaxially stretched it can be produced by, for example, dyeing | staining by immersing polyvinyl alcohol in the aqueous solution of iodine, and extending | stretching 3 to 7 times of original length. It can also be immersed in an aqueous solution such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride and the like as required. Furthermore, before dyeing, the polyvinyl alcohol-based film may be dipped in water and rinsed if necessary. In addition to being able to wash the stains and antiblocking agents on the surface of the polyvinyl alcohol film by washing the polyvinyl alcohol film with water, it is also possible to prevent unevenness such as uneven dyeing by swelling the polyvinyl alcohol film. is there. The stretching may be performed after staining with iodine, may be stretching while staining, or may be stretched and then stained with iodine. It can also be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

  In the present invention, a thin polarizer having a thickness of 10 μm or less can also be used. From the viewpoint of thinning, the thickness is preferably 1 to 7 μm. It is preferable that such a thin polarizer has less thickness unevenness, excellent visibility, and less dimensional change, so it is excellent in durability, and further, thickness reduction as a polarizing film can be achieved.

  Typical thin polarizers are disclosed in JP-A-51-069644, JP-A-2000-338329, WO 2010/100917, WO 2010/100917, or a patent. The thin-shaped polarizing film described in 4751481 specification and Unexamined-Japanese-Patent No. 2012-073563 can be mentioned. These thin polarizing films can be obtained by a manufacturing method including the steps of stretching a polyvinyl alcohol resin (hereinafter, also referred to as a PVA resin) layer and a stretching resin base material in the state of a laminate and dyeing. With this manufacturing method, even if the PVA-based resin layer is thin, it is possible to stretch without any problems such as breakage due to stretching by being supported by the stretching resin base material.

  Among the thin polarizing films described above, among the process of drawing in the state of a laminate and the process of dyeing, it can be drawn at a high magnification and the polarization performance can be improved. WO 2010/100917 pamphlet, or those obtained by the process including the step of stretching in an aqueous solution of boric acid as described in Japanese Patent No. 4751481 or Japanese Patent Application Laid-Open No. 2012-073563, particularly preferred is the patent What is obtained by the manufacturing method which includes the process of carrying out airborne extension auxiliary | assistant before extending | stretching in the boric-acid aqueous solution which is described in 4751481 specification or Unexamined-Japanese-Patent No. 2012-073563 is preferable.

(2) Transparent Protective Film As the transparent protective film, those conventionally used can be appropriately used. Specifically, a transparent protective film formed of a material excellent in transparency, mechanical strength, thermal stability, water blocking property, isotropy, etc. is preferable. For example, polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate And cellulose based polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene based polymers such as polystyrene and acrylonitrile / styrene copolymer (AS resin), polycarbonate based polymers and the like. In addition, polyolefins having polyethylene, polypropylene, cyclo-based or norbornene structure, polyolefin-based polymers such as ethylene / propylene copolymer, vinyl chloride-based polymers, amide-based polymers such as nylon and aromatic polyamides, imide-based polymers, sulfone-based polymers , Polyether sulfone polymers, polyetheretherketone polymers, polyphenylene sulfide polymers, vinyl alcohol polymers, vinylidene chloride polymers, vinyl butyral polymers, arylate polymers, polyoxymethylene polymers, epoxy polymers, or Blends of the above-mentioned polymers and the like are also mentioned as examples of the polymer forming the above-mentioned transparent protective film. The transparent protective film can also be formed as a cured layer of thermosetting resin such as acrylic resin, urethane resin, acrylic urethane resin, epoxy resin, and silicone resin, and ultraviolet curable resin.

  The thickness of the transparent protective film can be determined as appropriate, but generally it is about 1 to 500 μm from the viewpoints of strength, workability such as handleability, and thin film properties.

  The polarizer and the transparent protective film are preferably in close contact with each other via a water-based adhesive or the like. Examples of water-based adhesives include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latexes, water-based polyurethanes, water-based polyesters, and the like. In addition to the above, as an adhesive agent of a polarizer and a transparent protective film, an ultraviolet curable adhesive, an electron beam curable adhesive, etc. are mentioned. The adhesive for electron beam-curable polarizing film exhibits suitable adhesiveness to the above various viewing side transparent protective films. The adhesive used in the present invention can contain a metal compound filler.

  The surface of the transparent protective film to which the polarizer is not attached may be treated with a hard coat layer, an antireflective treatment, an antisticking treatment, or a treatment for diffusion or antiglare.

  Further, as the transparent protective film, any one having retardation and capable of functioning as an optical compensation layer can be used. When using the transparent protective film which has a phase difference, the phase difference characteristic can be suitably adjusted to the value required for optical compensation. As such a retardation film, a stretched film can be suitably used. The retardation film has a refractive index in the slow axis direction of nx, a refractive index in the in-plane fast axis direction of ny, and a refractive index in the thickness direction of nz: nx = ny> nz, nx> ny Those satisfying the relationship of> nz, nx> ny = nz, nx> nz> ny, nz = nx> ny, nz> nx> ny, nz> nx = ny are selected and used according to various applications. Be Note that nx = ny includes not only cases in which nx and ny are completely identical but also cases in which nx and ny are substantially the same. Also, ny = nz includes not only cases in which ny and nz are completely identical, but also cases in which ny and nz are substantially the same.

  When the polarizing film used in the present invention is used as a circularly polarizing plate for preventing reflection of an organic EL display device, the retardation film has a front surface retardation of the transparent protective film of 1⁄4 wavelength (about 100 to 170 nm). Preferably, it is a quarter wave plate.

  When using a retardation film as a transparent protective film, what has a transparent protective film in one side of a polarizer, and has a retardation film in the other side can be used suitably. Moreover, in that case, the installation place of the said adhesive layer is not specifically limited, It may be provided in the surface on the opposite side to the surface in contact with the polarizer of the said transparent protective film, The polarizer of retardation film It may be provided on the side opposite to the side in contact with the surface, but from the viewpoint of suppressing the deterioration of the organic EL element, it is preferably provided on at least one side or both sides.

  An example of a concrete structure of the polarizing film with an adhesive layer for organic EL display devices of this invention is shown to Fig.1 (a)-(c). As shown in FIG. 1 (a), adhesive layer 2 / transparent protective film 3 / polarizer 4 / retardation film 5, as shown in FIG. 1 (b), transparent protective film 3 / polarizer 4 / retardation As shown in film 5 / adhesive layer 2, as shown in FIG. 1 (c), each layer is in this order as adhesive layer 2 / transparent protective film 3 / polarizer 4 / retardation film 5 / adhesive layer 2; The laminated polarizing film 1 with an adhesive layer for organic EL display devices can be mentioned. In FIGS. 1 (a) and 1 (b), the pressure-sensitive adhesive layer 2 is the pressure-sensitive adhesive layer for the organic EL display device of the present invention, and in FIG. 1 (c), at least the two pressure-sensitive adhesive layers 2 are present. One of them may be the pressure-sensitive adhesive layer for the organic EL display device of the present invention, and both of them may be the pressure-sensitive adhesive layer for the organic EL display device of the present invention. Moreover, in FIG. 1, although the polarizing film 6 is a piece protection polarizing film comprised from the polarizer 4 and the transparent protective film 3, it is not limited to this, The polarizing film 4 and the retardation film 5 It may be both protective polarizing films further having a transparent protective film therebetween. Further, as described above, various functional layers such as a hard coat layer can be formed on the surface of the transparent protective film 3 which is not in contact with the polarizer 4.

Moreover, when the said retardation film is laminated | stacked on a polarizer through the adhesive layer, the said adhesive layer may be an adhesive layer for organic EL display apparatuses of this invention. That is, the polarizing film with a pressure-sensitive adhesive layer for an organic EL display device has a first pressure-sensitive adhesive layer, a transparent protective film, a polarizer, a second pressure-sensitive adhesive layer, a retardation film, and a third pressure-sensitive adhesive layer in this order
At least one pressure-sensitive adhesive layer of the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer, and the third pressure-sensitive adhesive layer may be the pressure-sensitive adhesive layer for the organic EL display device.

4. Organic EL Display Device The organic EL display device of the present invention uses at least one pressure-sensitive adhesive layer for an organic EL display device of the present invention and / or at least one polarizing film with an adhesive layer for an organic EL display device of the present invention. It features.

  As an example of a specific structure of an organic electroluminescence display, as shown, for example in FIG. 2, FIG. 3, cover glass or cover plastic 7 / adhesive layer 2b / transparent protective film 3 / polarizer 4 / retardation film 5 / adhesive layer 2a / organic EL display panel (OLED element panel) 8 (FIG. 2); cover glass or cover plastic 7 / adhesive layer 9 / transparent protective film 3 / polarizer 4 / retardation film 5 / adhesive As in the layer 2a / organic EL display panel 8 (FIG. 3), an organic EL display in which each layer is laminated in this order can be mentioned.

  Moreover, as an organic electroluminescence display, it can be used as an organic electroluminescence display with a touch panel which has a touch panel which further has at least 1 sensor film. For example, as shown in FIG. 4, cover glass or cover plastic 7 / adhesive layer 2c / sensor film 10 / adhesive layer 2b / transparent protective film 3 / polarizer 4 / retardation film 5 / adhesive layer 2a / organic As in the EL display panel 8 (FIG. 4), an organic EL display device in which each layer is laminated in this order can be mentioned.

  At least one of the pressure-sensitive adhesive layers 2 in each configuration may be the pressure-sensitive adhesive layer of the present invention, and all the pressure-sensitive adhesive layers 2 may be the pressure-sensitive adhesive layer of the present invention. In addition to the above, the organic EL display device of the present invention may include various functional layers such as a protective film and a hard coat layer. Moreover, in lamination | stacking of each layer, an adhesive layer and / or an adhesive bond layer can be used suitably. As pressure-sensitive adhesive layers other than the pressure-sensitive adhesive layer of the present invention, conventional pressure-sensitive adhesive layers used in the present field can be appropriately used.

  The pressure-sensitive adhesive layer for an organic EL display device according to the present invention comprises a touch panel having an organic EL panel, a circularly polarizing film provided in order from the viewing side of the organic EL panel, and at least one sensor film as shown in FIG. The present invention is suitably applied to the organic EL display device with a touch panel. In particular, the pressure-sensitive adhesive layer for an organic EL display device of the present invention is provided on the viewing side of the circularly polarizing film and is preferably provided so as to contact at least one sensor film forming a touch panel. Applies to In FIG. 4, the pressure-sensitive adhesive layer for an organic EL display device of the present invention is suitably applied as the pressure-sensitive adhesive layer 2c and / or the pressure-sensitive adhesive layer 2b in contact with the sensor film 10. In particular, as the pressure-sensitive adhesive layer 2b The use of is preferred. The pressure-sensitive adhesive layer 2b may be applied as a pressure-sensitive adhesive layer-attached polarizing film as shown in FIG. 1A, or may be applied as a pressure-sensitive adhesive layer between the sensor film and the circularly polarizing film. .

  In addition, also in FIG. 4, when using two or more sensor films 10, the adhesive layer for organic electroluminescent display apparatuses of this invention is applied suitably. For example, cover glass or cover plastic 7 / adhesive layer 2c / sensor film 10 / adhesive layer 2b '/ sensor film 10' / adhesive layer 2b / transparent protective film 3 / polarizer 4 / retardation film 5 / adhesive In the constitution of layer 2a / organic EL display panel 8, in addition to the pressure-sensitive adhesive layer 2c and / or the pressure-sensitive adhesive layer 2b, the pressure-sensitive adhesive layer 2b 'is suitably applied as a pressure-sensitive adhesive layer for an organic EL display device of the present invention Be done.

  The sensor film 10 in FIG. 4 is a capacitive touch sensor (film), and is a transparent conductive film in which a transparent conductive layer is provided on a glass plate or a transparent plastic film (especially a PET film). The contact of the pressure-sensitive adhesive layer for an organic EL display with the sensor film means contact with the transparent conductive layer.

  Examples of the transparent conductive layer include thin films of ITO (indium tin oxide), ZnO, SnO, and CTO (cadmium tin oxide). In addition, the transparent conductive layer can be formed of silver, copper, CNT (carbon nanotube) or the like. A transparent conductive layer can also employ metal mesh sensors, such as Ag nanowire and Ag / Cu. In addition, in FIG. 4, the capacitive touch panel using at least one sensor film 10 may have a lead-out wire formed of thin film copper or silver paste at an end portion of the sensor film.

  As described above, the pressure-sensitive adhesive layer for an organic EL display device of the present invention is used as a pressure-sensitive adhesive layer used in contact with at least one sensor film in the touch panel of the organic EL display device having the above configuration. In addition to organic EL display devices, it can be used as a touch panel pressure-sensitive adhesive layer used in contact with at least one sensor film in a touch panel.

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples. All parts and% in each example are based on weight.

Example 1
(Preparation of Acrylic Pressure-Sensitive Adhesive Composition)
Composed of 49 parts by weight of 2-ethylhexyl acrylate (2EHA), 30 parts by weight of isostearyl acrylate (ISTA), 18 parts by weight of N-vinyl-2-pyrrolidone (NVP) and 3 parts by weight of 4-hydroxybutyl acrylate (4HBA) In a monomer mixture, as a photopolymerization initiator, 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184, having an absorption band at a wavelength of 200 to 370 nm, manufactured by BASF Corp.) 0.035 parts by weight, 2, 2-dimethoxy-1 And 2-diphenylethane-1-one (trade name: IRGACURE 651, an absorption band at a wavelength of 200 to 380 nm, manufactured by BASF Corp.) 0.035 parts by weight, and then viscosity (measurement conditions: BH viscometer No. 1). 5 rotors, 10 rpm, measurement temperature 30 ° C) until it becomes about 20 Pa · s Ultraviolet rays were irradiated to obtain a prepolymer composition (polymerization ratio: 9%) in which a part of the above monomer mixture was polymerized. Next, to the prepolymer composition, 0.065 parts by weight of hexanediol diacrylate (HDDA), 100 parts by weight of the monofunctional monomer component in the obtained acrylic pressure-sensitive adhesive composition, a silane coupling agent (product Name: KBM-403, 0.3 part by weight from Shin-Etsu Chemical Co., Ltd., and 2,4-bis-[{4- (4) dissolved to a solid content of 10% in the same proportion of the monomer mixture as above. -Ethylhexyloxy) -4-hydroxy} -phenyl] -6- (4-methoxyphenyl) -1,3,5-triazine (trade name: Tinosorb S ultraviolet absorber (a), manufactured by BASF Japan Ltd.) 0. 8 parts by weight (solids weight) and bis (2,4,6-trimethyl benzoyl) -phenyl phosphine oxide (trade name: Irgacure 819, manufactured by BASF Japan Ltd.) 0. An acrylic pressure-sensitive adhesive composition was obtained by adding 10 parts by weight and stirring.

(Formation of adhesive layer)
The acrylic pressure-sensitive adhesive composition is coated on a release-treated film of a release film so that the thickness after forming the pressure-sensitive adhesive layer is 100 μm, and then, the surface of the pressure-sensitive adhesive composition layer is A release film was attached. Then, ultraviolet irradiation was performed on the conditions of illumination intensity: 6.5 mW / cm < ² >, light volume: 1500 mJ / cm < ² >, peak wavelength: 350 nm, the adhesive composition layer was photocured, and the adhesive layer was formed.

Examples 2 to 4 and Comparative Examples 1 to 3
An acrylic pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the type and amount of each component were changed as shown in Table 1 in the preparation of the acrylic pressure-sensitive adhesive composition in Example 1. . A pressure-sensitive adhesive layer was formed in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer was changed as shown in Table 1 using the acrylic pressure-sensitive adhesive composition.

(Manufacture of polarizing film (P))
A 25 μm-thick cycloolefin polymer (COP) film is bonded using a polyvinyl alcohol-based adhesive on the viewing side of a polarizer consisting of a 5 μm-thick drawn polyvinyl alcohol film impregnated with iodine, and the organic EL of the polarizer A retardation film (thickness: 56 μm, material: polycarbonate) was laminated on the surface of the display panel side using a polyvinyl alcohol-based adhesive to obtain a polarizing film (P). The polarization degree of the polarizing film was 99.995.

(Manufacture of polarizing film with adhesive layer)
The pressure-sensitive adhesive layer provided with the pressure-sensitive adhesive layer is laminated by laminating the pressure-sensitive adhesive layer obtained in the example or the comparative example on the viewing side of the polarizing film (P) (that is, the surface of a 25 μm-thick cycloolefin polymer (COP) film) A film was formed.

  The following evaluation was performed about the adhesive layer obtained by the Example or the comparative example, and the polarizing film with an adhesive layer. The results are shown in Table 1.

<Measurement of Tg of adhesive layer by dynamic viscoelasticity>
The pressure-sensitive adhesive layer obtained in Examples or Comparative Examples was laminated to form a pressure-sensitive adhesive laminate layer having a thickness of about 2 mm. The pressure-sensitive adhesive laminate layer is punched into a disk shape having a diameter of 7.9 mm, and this is sandwiched between parallel plates and fixed, and the measurement conditions described below are obtained using a dynamic viscoelasticity measuring device (ARES, manufactured by Rheometrics). The loss modulus G ′ ′ and the storage modulus G ′ were measured. The peak value of the ratio of loss modulus to storage modulus (G ′ ′ / G ′) = Tan δ was read as the Tg of the pressure-sensitive adhesive layer.
Measurement: Shear mode Temperature range: -50 ° C to 150 ° C
· Heating rate: 5 ° C / min
・ Frequency: 1 Hz
The storage elastic modulus G ′ (25 ° C.) is preferably 5.0 × 10 ⁴ Pa or more and 2.5 × 10 ⁵ Pa or less. The storage elastic modulus G ′ (80 ° C.) is preferably 1.2 × 10 ⁴ Pa or more and 1.0 × 10 ⁵ Pa or less. It is preferable that the storage elastic modulus G ′ (25 ° C.) satisfies 5.0 × 10 ⁴ Pa or more in order to secure processability at the time of punching, and satisfies 2.5 × 10 ⁵ Pa or less Is preferable in order to ensure the followability to the printing step of the decorative printing such as the cover glass. It is preferable that the storage elastic modulus G ′ (80 ° C.) satisfies the above-mentioned 1.2 × 10 ⁴ Pa or more in order to suppress peeling of a film or the like at the time of charging to high-temperature reliability, 1.0 × 10 ⁵ Satisfying Pa or less is preferable because air bubbles generated in bonding can be favorably removed during autoclave (pressure degassing) processing.

<Measurement of transmittance and hue of pressure-sensitive adhesive layer having dye absorber and UV absorber>
One release film is peeled off from the pressure-sensitive adhesive layer obtained in Examples or Comparative Examples, and a slide glass (trade name: white polishing No. 1, thickness: 0.8 to 1.0 mm, total light transmission) Rate: 92%, haze: 0.2%, it bonded together to Matsunami Glass Industry Co., Ltd. product). Further, the other release film is peeled off, the same slide glass is pasted, autoclaved (50 ° C., 0.5 MPa, 15 minutes), and a test piece having a slide glass / adhesive layer / slide glass layer structure Was produced. The produced test piece was measured by a spectrophotometer (product name: U4100, manufactured by Hitachi High-Technologies Corporation). The transmittance in the wavelength range of 350 nm to 780 nm was measured. The transmittance at a wavelength of 380 nm and a wavelength of 450 nm is shown in Table 1.

<Total light transmittance, haze>
One release film is peeled off from the pressure-sensitive adhesive layer obtained in Examples or Comparative Examples, and a slide glass (trade name: white polishing No. 1, thickness: 0.8 to 1.0 mm, total light transmission) Rate: 92%, haze: 0.2%, it bonded together to Matsunami Glass Industry Co., Ltd. product). Furthermore, the other release film was peeled off to prepare a test piece having a pressure-sensitive adhesive layer / slide glass layer structure. The total light transmittance and haze value in the visible light region of the test piece were measured using a haze meter (device name: HM-150, manufactured by Murakami Color Research Laboratory).

<Evaluation of dielectric constant>
Measure the relative dielectric constant at a frequency of 100 kHz with the following device by sandwiching the pressure-sensitive adhesive layer obtained in the example or the comparative example (a sheet obtained by peeling off the silicone-treated PET film from the pressure-sensitive adhesive sheet) between a copper foil and an electrode. did. The measurement produced three samples and made the average of the measured value of those three samples the relative dielectric constant.
The relative dielectric constant at a frequency of 100 kHz of the pressure-sensitive adhesive layer was measured according to JIS K 6911 under the following conditions.
Measurement method: volumetric method (instrument: Agilent Technologies 4294A Precision Impedance Analyzer)
Electrode configuration: 12.1 mm diameter, 0.5 mm thick aluminum plate Counter electrode: 3 oz copper plate Measurement environment: 23 ± 1 ° C., 52 ± 1% RH

<Measurement of gel fraction>
A predetermined amount (initial weight W1) is taken out from the pressure-sensitive adhesive layer obtained in the example or the comparative example, immersed in an ethyl acetate solution, allowed to stand at room temperature for 1 week, the insoluble matter is taken out, and the dried weight ( W2) was measured and determined as follows.
Gel fraction (%) = (W2 / W1) x 100

<Adhesiveness>
A sheet piece of 100 mm in length and 20 mm in width was cut out from the pressure-sensitive adhesive layer obtained in Examples or Comparative Examples. Next, one release film of the pressure-sensitive adhesive layer was peeled off, and a PET film (trade name: LUMIRROR S-10, thickness: 25 μm, manufactured by Toray Industries, Inc.) was attached (backed). Next, the other release film is peeled off, and pressed as a test plate to a glass plate (trade name: soda lime glass # 0050, manufactured by Matsunami Glass Industry Co., Ltd.) under a pressure condition of 1 reciprocation with a 2 kg roller. The sample comprised from a test board / adhesive layer / PET film was produced. The obtained sample is autoclaved (50 ° C., 0.5 MPa, 15 minutes), and then 23 ° C., 50% R.H. H. It was allowed to cool for 30 minutes under the atmosphere of After leaving to cool, a tensile tester (apparatus name: Autograph AG-IS, manufactured by Shimadzu Corporation) is used, according to JIS Z0237, 23 ° C., 50% R.H. H. The pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer / PET film) was peeled off from the test plate under the conditions of a tensile speed of 300 mm / min and a peeling angle of 180 ° under an atmosphere of 1, and the 180 ° peel adhesion (N / 20 mm) was measured.

Drop impact resistance test
A cycloolefin polymer (COP) having a conductive ITO layer on one side of a chemically strengthened glass (100 mm in length, 100 mm in width, 1.3 mm in thickness) on one side with an acrylic adhesive layer of 25 μm in thickness and the same size. The substrate side of the film (55 μm thick) was attached. Furthermore, the pressure-sensitive adhesive layer prepared in Examples and Comparative Examples is cut into a size of 50 mm long and 50 mm wide so that the central portion of the pressure-sensitive adhesive layer overlaps the central portion on the ITO layer side of the COP film with conductive ITO layer. Test pieces (chemically reinforced glass / adhesive layer / conductive) by laminating the central part of a black acrylic plate (110 mm long, 120 mm wide, 1 mm thick) to the central part. An ITO layer-attached COP film (thickness 55 μm) / pressure-sensitive adhesive layer / acrylic plate of Example or Comparative Example was produced. The obtained test piece is autoclaved (50 ° C., 0.5 MPa, 15 minutes), and then 23 ° C., 50% R.H. H. It was allowed to cool for 24 hours under the atmosphere of The test pieces prepared in this manner were fixed to a horizontally installed base with both sides of the acrylic plate so that the vertical and horizontal planes were vertical. On the other hand, a fulcrum was determined on the upper side (53 cm above the center of the test piece) on which the test piece was placed, one end of a 53 cm long string was fixed to the fulcrum, and a lead ball of 113 g was fixed to the other end.
The drop impact resistance test was performed by dropping the lead ball in a pendulum manner from the same height as the fulcrum and causing the lead ball to collide with the acrylic plate side of the fixed test piece (central part of the vertical and horizontal planes). The peeling distance when this collision was performed 20 times was measured. The peeling distance is a distance at which peeling was observed from the edge and the corner of the adhesive layer of the example of the test piece or the comparative example. The thing whose maximum value of peeling distance is 5 mm or less was taken as pass.

In Table 1,
2EHA is 2-ethylhexyl acrylate;
ISTA is isostearyl acrylate;
NVP is N-vinyl-2-pyrrolidone;
4HBA is 4-hydroxybutyl acrylate;
HEA is 2-hydroxyethyl acrylate;
HDDA is hexanediol diacrylate;
DPHA is dipentaerythritol hexaacrylate;
TMPTA is trimethylolpropane triacrylate;
UV absorber a is 2,4-bis-[{4- (4-ethylhexyloxy) -4-hydroxy} -phenyl] -6- (4-methoxyphenyl) -1,3,5-triazine (trade name) : Tinosorb S, maximum absorption wavelength of absorption spectrum: 346 nm, manufactured by BASF Japan Ltd .;
UV absorber b is 2- (2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol (commodity Name: Tinuvin 928, maximum absorption wavelength of absorption spectrum: 349 nm, manufactured by BASF Japan Ltd .;
Dye compound c is BONASORB UA3911 (trade name, indole compound, maximum absorption wavelength of absorption spectrum: 398 nm, half width: 48 nm, manufactured by Orient Chemical Industries, Ltd.);
Irg 819 is bis (2,4,6-trimethyl benzoyl) -phenyl phosphine oxide (trade name: Irgacure 819, manufactured by BASF Japan Ltd.);
KBM-403 represents a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.).

1 Polarizing film with pressure-sensitive adhesive layer for organic EL display device 2 pressure-sensitive adhesive layer (a, b, c)
3 Transparent protective film 4 Polarizer 5 Retardation film 6 Polarizing film 7 Cover glass or cover plastic 8 Organic EL panel 9 Adhesive layer 10 Sensor film

Claims (22)

A pressure-sensitive adhesive layer for an organic EL display device, which is formed of a pressure-sensitive adhesive composition containing a (meth) acrylic polymer and a UV absorber,
The (meth) acrylic polymer is an alkyl (meth) acrylate (C) having an alkyl group having 8 or less carbon atoms at the ester end and an alkyl (meth) acrylate (B) having an alkyl group having 12 to 24 carbon atoms at the ester end Obtained by polymerizing a monomer component containing a monofunctional monomer component containing
The ratio (a: wt%) of the alkyl (meth) acrylate (A) and the ratio (b: wt%) of the alkyl (meth) acrylate (B) in 100 wt% of the monofunctional monomer component are represented by the following formulas (1) and the expression (2) are satisfied,
Formula (1): 60 ≦ {(a) + (b)}
Formula (2): 1.4 ≦ {(a) / (b)} ≦ 2
And the pressure-sensitive adhesive layer is
The peak value (Tg) of tan δ when dynamic viscoelasticity is measured at a frequency of 1 Hz is −20 to −5 ° C.
The transmittance at a wavelength of 380 nm is 10% or less, and the transmittance at a wavelength of 450 nm is 85% or more,
A pressure-sensitive adhesive layer for an organic EL display device, having a total light transmittance of 85% or more and a haze of 1% or less.   The pressure-sensitive adhesive layer for an organic EL display device according to claim 1, wherein the maximum absorption wavelength of the absorption spectrum of the ultraviolet absorber is in a wavelength range of 300 to 400 nm.   3. The organic EL display device according to claim 1, wherein the monofunctional monomer component further contains any at least one cohesive monomer selected from a cyclic nitrogen-containing monomer and an alicyclic structure-containing monomer. Adhesive layer.   4. The pressure-sensitive adhesive layer for an organic EL display device according to claim 3, wherein a proportion of the cohesive monomer in the monofunctional monomer component is 10 to 22% by weight.   The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 4, wherein the monofunctional monomer component further contains a hydroxyl group-containing monomer.   The pressure-sensitive adhesive layer for an organic EL display device according to claim 5, wherein a proportion of the hydroxyl group-containing monomer in the monofunctional monomer component is 1.5 to 10% by weight.   The organic EL display according to any one of claims 1 to 6, wherein the monomer component further contains a polyfunctional monomer in an amount of 3 parts by weight or less based on 100 parts by weight of the monofunctional monomer component. Device adhesive layer.   The organic EL display device according to any one of claims 1 to 7, wherein the pressure-sensitive adhesive composition further contains a dye compound having a maximum absorption wavelength of absorption spectrum in a wavelength range of 380 to 430 nm. Adhesive layer.   The organic composition according to any one of claims 1 to 8, wherein the pressure-sensitive adhesive composition further contains a silane coupling agent in an amount of 3 parts by weight or less based on 100 parts by weight of the monofunctional monomer component. Adhesive layer for EL display devices.   The organic EL display according to any one of claims 1 to 9, wherein the pressure-sensitive adhesive composition further contains a crosslinking agent in an amount of 3 parts by weight or less based on 100 parts by weight of the monofunctional monomer component. Device adhesive layer.   The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 10, wherein the pressure-sensitive adhesive composition further contains a photopolymerization initiator.   The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 11, wherein a relative dielectric constant at a frequency of 100 kHz is 3.5 or less.   The gel fraction is 50 to 95% by weight, The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 12.   The organic EL display device according to any one of claims 1 to 13, wherein the pressure-sensitive adhesive layer has a 180 degree peel adhesion (peeling speed of 300 mm / min) to alkali-free glass of 7 N / 20 mm or more. Adhesive layer.   The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 14, having a separator on at least one side.   A polarizing film with a pressure-sensitive adhesive layer for an organic EL display device, comprising: a polarizing film; and the pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 15.   The polarizing film is provided with a transparent protective film on one side of a polarizer and has a retardation film on the other side, and the pressure-sensitive adhesive layer for an organic EL display device is the polarization of the retardation film. The adhesive for an organic EL display device according to claim 16, characterized in that it is provided on the side opposite to the side in contact with the child and / or on the side opposite to the side in contact with the polarizer of the transparent protective film. Layered polarizing film. A pressure-sensitive adhesive layer-carrying polarizing film comprising a first pressure-sensitive adhesive layer, a transparent protective film, a polarizer, a second pressure-sensitive adhesive layer, a retardation film, and a third pressure-sensitive adhesive layer in this order,
17. The device according to claim 16, wherein at least one pressure-sensitive adhesive layer among the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer, and the third pressure-sensitive adhesive layer is the pressure-sensitive adhesive layer for the organic EL display device. The polarizing film with the adhesive layer for organic electroluminescence display as described in it.   The pressure-sensitive adhesive layer-attached polarizing film for an organic EL display device according to claim 17 or 18, wherein the retardation film is a quarter wavelength plate, and the polarizing film is a circular polarizing film.   A pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 14, or at least one polarizing film with a pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 16 to 19 An organic EL display device characterized by The organic EL display device is an organic EL display device with a touch panel including a touch panel having an organic EL panel, a circularly polarizing film provided in order from the viewing side of the organic EL panel, and at least one sensor film,
The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 14 is provided in contact with at least one sensor film on the viewing side of the circularly polarizing film. An organic EL display device according to claim 20. 22. The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 15, which is used in the touch panel of the organic EL display device according to claim 21 in contact with at least one sensor film.

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